Haswell compatibility with Corsair power supplies

By Jonny Gerow, on May 09, 2013 07:00 AM

A report recently published over at the VR-Zone discussing the new 4th generation Intel Core processors, code-named "Haswell", and their ability to go into a lower power sleep state than any previous processor has caused some concern about PSU compatability with the new processor.

When an Intel Core (i3, i5, i7) processor is idle, it goes into a sleep state that requires less power than when the CPU is active. Since the motherboard voltage regulation modules that provide power to the CPU gets their power from the power supply's +12V rail, these sleep states can dramatically reduce the load on the power supply's +12V rail.

According to Intel's presentation at IDF, the new Haswell processors enter a sleep state called C7 that can drop processor power usage as low as 0.05A. Even if the sleeping CPU is the only load on the +12V rail, most power supplies can handle a load this low. The potential problem comes up when there is still a substantial load on the power supply's non-primary rails (the +3.3V and +5V). If the load on these non-primary rails are above a certain threshold (which varies by PSU), the +12V can go out of spec (voltages greater than +12.6V). If the +12V is out of spec when the motherboard comes out of the sleep state, the PSU's protection may prevent the PSU from running and will cause the power supply to "latch off". This will require the user to cycle the power on their power supply using the power switch on the back of the unit.

While we are still working with Intel on the details of the testing methodology they use to check PSUs for Haswell compatibility, it is already known that a power supply that uses DC to DC for the non-primary rails (the +3.3V and +5V) will not have an issue with the new low power sleep states. This is because a DC to DC buck converter is used to convert +12V to +3.3V and +5V. This means that no matter what load the CPU puts on the power supply, there will always be a load on the +12V because the +12V is required to provide power to +3.3V and +5V.

Corsair utilizes this DC to DC technology in most of their power supplies. Starting with the CX750 and CX750M and moving all of the way through the GS Series, TX and TX-M Series, the HX Series, both the AX Series Gold and AX Series Platinum, and the new AXi Series. So whatever your budget, if you choose Intel's new Haswell processor and wish to utilize the new, low power C7 sleep state, Corsair has a power supply for you.

PSU Series

Model

Haswell Compatibility

Comment

AXi

AX1200i

Yes

100% Compatible with Haswell CPUs

AX860i

Yes

100% Compatible with Haswell CPUs

AX760i

Yes

100% Compatible with Haswell CPUs

AX
(Gold and Platinum)

AX1200

Yes

100% Compatible with Haswell CPUs

AX860

Yes

100% Compatible with Haswell CPUs

AX850

Yes

100% Compatible with Haswell CPUs

AX760

Yes

100% Compatible with Haswell CPUs

AX750

Yes

100% Compatible with Haswell CPUs

AX650

Yes

100% Compatible with Haswell CPUs

HX
(Silver, Gold and HX1000)

HX1050

Yes

100% Compatible with Haswell CPUs

HX1000

Yes

100% Compatible with Haswell CPUs

HX850

Yes

100% Compatible with Haswell CPUs

HX750

Yes

100% Compatible with Haswell CPUs

HX650

Yes

100% Compatible with Haswell CPUs

HX
(Legacy Bronze
and below)

HX620

TBD

Likely compatible — currently validating

HX520

TBD

Likely compatible — currently validating

HX650

TBD

Likely compatible — currently validating

HX450

TBD

Likely compatible — currently validating

TX-M
(All Versions)

TX950M

Yes

100% Compatible with Haswell CPUs

TX850M

Yes

100% Compatible with Haswell CPUs

TX750M

Yes

100% Compatible with Haswell CPUs

TX650M

Yes

100% Compatible with Haswell CPUs

TX550M

Yes

100% Compatible with Haswell CPUs

RM
(All Versions)

RM450

Yes

100% Compatible with Haswell CPUs

RM550

Yes

100% Compatible with Haswell CPUs

RM650

Yes

100% Compatible with Haswell CPUs

RM750

Yes

100% Compatible with Haswell CPUs

RM850

Yes

100% Compatible with Haswell CPUs

RM1000

Yes

100% Compatible with Haswell CPUs

TX
(All Versions)

TX950

Yes

100% Compatible with Haswell CPUs

TX850

Yes

100% Compatible with Haswell CPUs

TX750

Yes

100% Compatible with Haswell CPUs

TX650

Yes

100% Compatible with Haswell CPUs

TX550

Yes

100% Compatible with Haswell CPUs

GS
(Current V3)

GS800

Yes

100% Compatible with Haswell CPUs

GS700

Yes

100% Compatible with Haswell CPUs

GS600

Yes

100% Compatible with Haswell CPUs

GS
(Legacy V2)

GS600

TBD

Likely compatible — currently validating

GS500

TBD

Likely compatible — currently validating

GS
(Legacy V1)

GS800

Yes

100% Compatible with Haswell CPUs

GS700

Yes

100% Compatible with Haswell CPUs

GS600

Yes

100% Compatible with Haswell CPUs

GS500

TBD

Likely compatible — currently validating

CS-M

CS750M

Yes

100% Compatible with Haswell CPUs

CS650M

Yes

100% Compatible with Haswell CPUs

CS550M

Yes

100% Compatible with Haswell CPUs

CS450M

Yes

100% Compatible with Haswell CPUs

CX-M

CX750M

Yes

100% Compatible with Haswell CPUs

CX600M

TBD

Likely compatible — currently validating

CX500M

TBD

Likely compatible — currently validating

CX430M

TBD

Likely compatible — currently validating

CX

CX750

Yes

100% Compatible with Haswell CPUs

CX600

TBD

Likely compatible — currently validating

CX500

TBD

Likely compatible — currently validating

CX430

TBD

Likely compatible — currently validating

VX
(Legacy)

VX450

TBD

Likely compatible — currently validating

VX550

Yes

100% Compatible with Haswell CPUs

VS

VS650

TBD

Likely compatible — currently validating

VS550

TBD

Likely compatible — currently validating

VS450

TBD

Likely compatible — currently validating

VS350

TBD

Likely compatible — currently validating

As we work with Intel over their Haswell testing methodology and discuss with motherboard manufacturers about the different ways they may address potential compatibility problems with power supplies, we will keep you updated right here on this blog. We will also continue to test legacy product (discontinued product) and keep the list updated in this way as well.